Radio link check

ABSTRACT

The present invention is directed towards a method, a link check device, and a portable communication device for communication link check. The link check device ( 102 ) comprises a receiver unit ( 104 ) for receiving and monitoring information including a power control signal from a base station on a first link ( 109 ). A first and second signal generating unit ( 110, 112 ) connected to said receiver unit ( 104 ) provide a first and second noise signal (R 1 , R 2 ), which are transmitted to a combining unit ( 114 ) to provide a third signal representing signal (R 3 ) strength for communication links.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to radio link check in a portablecommunication device. More particularly it relates to a method and adevice for radio link check in a portable communication device for auser to be able to choose a more favourable location for radio linkconnection.

BACKGROUND

It is well known that in radio communication systems including basestations and mobile terminals communicating with each other on radiolinks, calls typically in fringe areas can be lost due to bad radio linkpreformace, in some cases even without a warning to a user, which ofcourse causes problems, or at least irritation to the user of a mobileterminal. Often, it is not possible for the user to select a locationwhich has better radio conditions, whereby radio link performance isjust a matter of coincidence.

DESCRIPTION OF RELATED ART

There are several conventional techniques for selecting a location withbetter radio conditions. For example, base station strength, i.e. thestrength of the radio link from the base station to the mobile terminalis often shown graphically on a display of the mobile terminal. The basestation signal strength indicates a so-called “down-link” connection,which unfortunately is normally of little help where coverage is bad,since the radio link from the mobile terminal up to the base station,the so-called “up-link” is often the weakest link, i.e. the real causeof the bad radio link performance. Therefore, the known solution onlytaking the down-link signal strength in account to select better radioconditions is not satisfactory.

There is thus a need to solve the problem with the signal strength ofthe weakest radio link to secure a better determination of better radioconditions.

SUMMARY OF INVENTION

The present invention is thus directed towards solving the problem withthe radio signal strength including the weakest radio link.

This is achieved by using both down- and uplink signal strength toprovide determination of better radio conditions.

One object of the present invention is to provide a method forcommunication link check using both down- and uplink signal strength.

According to a first aspect of this invention, this object is achievedby a method for communication link check in a portable communicationdevice, said method comprising the steps of:

-   -   receiving information including power control commands from a        base station on a first link;    -   monitoring said first link for base station signal strength and        power control commands;    -   providing a first signal strength representation signal based on        base station signal strength;    -   providing a second signal strength representation signal based        on the power control commands; and    -   combining said first and second representation signals to        provide a third signal strength representation signal which is        transmitted to a user presentation unit for communication link        check.

Thus, the invention provides signal strength representation using boththe down-link as well as the uplink, which improves determination ofactual signal strength including also the weakest link.

A second aspect of the present invention is directed towards a methodincluding the features of the first aspect, in which the said first andsecond signal strength representation signals are noise signals.

A third aspect of the present invention is directed towards a methodincluding the features of the first aspect, in which the step ofcombining said first and second signal strength representation signalsincludes adding said noise signals.

A fourth aspect of the present invention is directed towards a methodincluding the features of any one of the first aspect to the thirdaspect, including the step wherein the third signal is transmitted asaudible noise to a user audio output.

A fifth aspect of the present invention is directed towards a methodincluding the features of the fourth aspect wherein the third signal ispresented visually as well.

Another object of the present invention is to provide a communicationlink check device for a portable communication device, that easilyenables a user to find a location having better radio conditions.

According to a sixth aspect of the present invention, this object isachieved by:

-   -   a communication link check device for a portable electronic        device device, said communication link check device comprising:        -   a receiver unit provided for receiving information including            a power control signal from a base station on a first link;        -   a monitoring unit connected to said receiver unit for            monitoring said first link for base station signal strength            and power control;        -   a first signal generating unit connected to said receiver            unit, said first signal generating unit being arranged to            provide a first signal strength representation signal based            on the base station signal strength;        -   a second signal generating unit connected to said receiver            unit, said second signal generating unit being arranged to            provide a second signal strength representation signal based            on the power control signal;        -   a combining unit connected to said first and second signal            generating units arranged to combine the first and second            signal strength representation signals to a third signal            strength representation signal; and        -   a control unit connected to the receiver unit, first and            second signal generating units and combining unit for            control thereof and being arranged to provide the third            signal to a user presentation unit for communication link            check.

A seventh aspect of the present invention is directed towards acommunication link check device comprising the features of the sixthaspect, wherein the first first and second signal generating units arenoise generating units.

An eight aspect of the present invention is directed towards acommunication link check device comprising the features of the sixth orthe seventh aspect, wherein the user presentaion unit is an audio useroutput and/or a visual user presentation unit.

According to a ninth aspect of the present invention, there is provideda portable communication device comprising:

-   -   a communication link check device for a portable electronic        device device, said communication link check device comprising:        -   a receiver unit provided for receiving information including            a power control signal from a base station on a first link;        -   a monitoring unit connected to said receiver unit for            monitoring said first link for base station signal strength            and power control;        -   a first signal generating unit connected to said receiver            unit, said first signal generating unit being arranged to            provide a first signal strength representation signal based            on the base station signal strength;        -   a second signal generating unit connected to said receiver            unit, said second signal generating unit being arranged to            provide a second signal strength representation signal based            on the power control signal;        -   a combining unit connected to said first and second signal            generating units arranged to combine the first and second            signal strength representation signals to a third signal            strength representation signal; and        -   a control unit connected to the receiver unit, first and            second signal generating units and combining unit for            control thereof and being arranged to provide the third            signal to a user presentation unit for communication link            check.

A tenth aspect of the present invention is directed towards a portablecommunication device, wherein the device is a cellular phone, a smartphone or a PDA.

The present invention has the following advantages over the state of theart:

Firstly, by also using the power control signal transmitted from thebase station to the mobile station, the uplink, which is typically theweakest link, is also monitored so that a user can find a betterlocation having better radio conditions. The power control signal can beused to represent the uplink radio conditions, since this signal isdepending on the transmission on the uplink. The base station instructsthe mobile station to increase or decrease transmission power in a wayknown per se.

Secondly, since a better location can be found with sufficent up- anddownlinks, transmit power in the portable electronic device can be lessto save battery, as well as reduce interference on neighboring channels.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components, but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described in more detail in relationto the enclosed drawings, in which:

FIG. 1 shows a communication link check device for a portablecommunication device; and

FIG. 2 shows a method for communication link check in a portablecommunication device.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be given to FIG. 1 showing a communication link checkdevice according to one preferred embodiment of the invention. In thisfigure, the communication link check device 102 is controlled by acontrol unit 103 included in said communication link check device, 102.Said communication link check device 102 also comprises a receiver unit104 provided for communication with a base station (not shown) in a wayknown per se. The communication link check device 102 also includes amonitoring unit 108 for monitoring a first link 109 for base stationsignal strength and power control commands, and is connected to orlocated within the receiver unit, 104. The communication link checkdevice 102 further comprises a first signal strength representationsignal generating unit 110 connected to the receiver unit 104,preferably a first noise generating unit for providing a first signalstrength representation signal R₁, preferably a first noise signal basedon the base station signal strength. The communication link check device102 further comprises a second signal strength representation signalgenerating unit 112 connected to the receiver unit 104, preferably asecond noise generating unit for providing a second signal strengthrepresentation signal R₂, typically a second noise signal, based onconventional power control commands received from the base station in away known per se. Furthermore, the communication link check devicecomprises a signal combining unit 114 for combining the first and secondsignal strength representation signals R₁ and R₂, i.e. in thisembodiment the first and second noise signals to a third signal strengthrepresentation signal R₃ provided for link check, typically audible linkcheck by means of transmitting the third signal strength representationsignal R₃ to a user audio output 120.

FIG. 2 presents a flow-chart of one embodiment of a method forcommunication link check in a portable communication device. Referencewill also be given to FIG. 1.

With reference to FIG. 1 and FIG. 2, the method for communication linkcheck will now be explained. This method starts by from an incomingradio signal receiving information including a power control signal froma base station on a first link 109 (the so-called down-link), step 202,by means of a receiver unit 104, in a way known per se, as shown inFIG. 1. It is assumed that the receiver unit 104 receives the radiosignal and demodulates it in a way known per se, which will thereforenot be described in more detail herein. Thereafter, the monitoring unit108 monitors the first link 109 for base station signal strength, step204.

In the first signal generating unit 110, preferably a first noisegenerating unit connected to said receiver unit 104, the first signalstrength representation signal R₁, preferably a first noise signal basedon the base station signal strength is generated, typically in a wayknown per se, step 206.

In the second signal generating unit 112, preferably a second noisegenerating unit connected to said receiver unit 104, the second signalstrength representation signal, preferably a second noise signal basedon the received power control signal, is generated, step 208. The powercontrol signal is a conventional power control signal sent from the basestation to the communication link control device for controllingtransmitted up-link power, i.e. the signal from a portable communicationdevice including the communication link check device according to theinvention. The power control signal is received and decoded in a wayknown per se, which will therefore not be described in more detail andcan be transformed into a noise signal or other representation signal ina way known per se.

The noise generating units do not have to be separate units, butalternatively, they can be included in one unit only, provided that twosignal strength representation signals can be generated. Also, they canbe integrated with the receiver unit instead of being linked thereto asdescribed.

In a signal combining unit 114, the first and second signal strengthrepresentation signals R₁, R₂ are combined, preferably added, step 210to a third signal strength representation signal R₃. This third signalstrength representation signal R₃ is transmitted to a user outputprovided for link check, preferably as an audible noise signaltransmitted to the user of a portable communication device comprisingthe link check device according to the invention.

In this way, noise will appear to a user as receiver noise comparable toprior analog systems (for instance NMT 450) in which a user could hearnoise decreasing when he/she moved to a more favourable location asregards radio signal conditions. However, also in prior analog systemsonly down-link noise could be heard, which as described earlier is oftenof little help since the up-link is typically the weakest point.

Alternatively, according to another embodiment of the invention, thethird signal R₃ representing overall signal strength of both down-linkas well as uplink can be presented for the user in some other way thanas an audible noise signal. For instance, some visual means may beprovided instead or as a complement to the audible representation, evenif this solution is typically less suitable for the user than theaudible alternative which is preferred.

According to a preferred embodiment of the invention, the portablecommunication device, comprising the link check device is a cellulartelephone, a smart-phone or a PDA.

The invention is characterised in that both uplink as well as down-linktransmission are monitored to help the user to find a better locationhaving both links optimised. Of course, if conditions are too bad, evenmoving from one location to another might not help, but nevertheless inmost or at least many situations the invention will help the user tofind a better location. An example could be a situation where the userhas a headset connected to a cellular phone, whereby he/she can move thecellular phone just a little bit to improve radio conditions. Besidesimproving radio conditions, the invention is also applicable to savebattery as a consequence of less transmitting power required for theuplink. Thus, a user can use this invention to save battery as well.

Other situations when the invention may not be able to help the user arefor instance fast fading conditions such as those that occurs duringdriving typically at high speed. In these cases, radio conditions changetoo fast. In a embodiment of the invention additional circuits are addedto inhibit the function according to the invention in those conditions.Thus, the invention is most suitable for a user standing still, but isnot limited to this.

According to the above described embodiment of the present inventionradio communication between the base station and the mobile is effectedtypically using TDMA/FDMA. However, this is by no means intended tolimit the invention in any sense, since communication could also beeffected for instance by means of CDMA or any other suitable technique.In the following, the term “down-link” refers to the radio transmissionof information bearing signals from the base station to the mobilestation. Similarly, the term “uplink”, refers to the radio transmissionof information bearing signals from the mobile stations to the basestation.

It is emphasized that this invention can be varied in many ways, ofwhich the alternative embodiments below only are examples of a few.These different embodiments are hence non-limiting examples. The scopeof this present invention, however, is only limited by the subsequentlyfollowing patent claims.

The portable communication device can be any one of a variety of devicelike a personal digital assistant (PDA), a cellular phone, .

1. A method for communication link check in a portable communicationdevice, said method comprising: receiving information including powercontrol commands from a base station on a first link (202); monitoringsaid first link for base station signal strength and power controlcommands (204); providing a first signal strength representation signalbased on base station signal strength (206); providing a second signalstrength representation signal based on the power control commands(208); and combining (210) said first and second signal strengthrepresentation signals (R₁, R₂) to provide a third signal strengthrepresentation signal (R₃) which is transmitted to a user presentationunit for communication link check (212).
 2. Method according to claim 1,wherein said first and second signal strength representation signals(R₁, R₂) are noise signals.
 3. Method according to claim 2, wherein thestep of combining (210) said first and second signal strengthrepresentation signals (R1, R2) includes adding said noise signals. 4.Method according to claim 1, wherein said third signal (R₃) istransmitted as audible noise to a user audio output (120).
 5. Methodaccording to claim 4, wherein said third signal (R₃) is presentedvisually.
 6. Communication link check device for a portable electronicdevice, said communication link check device (102) comprising: areceiver unit (104) provided for receiving information including a powercontrol signal from a base station on a first link; a monitoring unit(108) connected to said receiver unit (104) for monitoring said firstlink (109) for base station signal strength and power control; a firstsignal generating unit (110) connected to said receiver unit (104), saidfirst signal generating unit being arranged to provide a first signalstrength representation signal (R₁) based on the base station signalstrength; a second signal generating unit (112) connected to saidreceiver unit (104), said second signal generating unit (112) beingarranged to provide a second signal strength representation signal (R₂)based on the power control signal; a combining unit (114) connected tosaid first and second signal generating units (110, 112) arranged tocombine the first and second signal strength representation signals (R₁,R₂) to form a third signal strength representation signal (R₃); and acontrol unit (103) connected to the receiver unit (104), first andsecond signal generating units (110, 112) and combining unit (114) forcontrol thereof and being arranged to provide the third signal strengthrepresentation signal (R₃) to a user presentation unit (120) forcommunication link check.
 7. Communication link check device accordingto claim 6, wherein said first and second signal generating units (110,112) are noise generating units.
 8. Communication link check deviceaccording to claim 6, wherein the user presentation unit (120) includesat least one of an audio user output or a visual presentation unit. 9.Portable communication device comprising: a communication link checkdevice for a portable electronic device, said communication link checkdevice (102) comprising: a receiver unit (104) provided for receivinginformation including a power control signal from a base station on afirst link; a monitoring unit (108) connected to said receiver unit(104) for monitoring said first link (109) for base station signalstrength and power control; a first signal generating unit (110)connected to said receiver unit (104), said first signal generating unitbeing arranged to provide a first signal strength representation signal(R₁) based on the base station signal strength; a second signalgenerating unit (112) connected to said receiver unit (104), said secondsignal generating unit (112) being arranged to provide a second signalstrength representation signal (R₂) based on the power control signal; acombining unit (114) connected to said first and second signalgenerating units (110, 112) arranged to combine the first and secondsignal strength representation signals (R₁, R₂) to provide a thirdsignal strength representation signal (R₃); and a control unit (103)connected to the receiver unit (104), first and second signal generatingunits (110, 112) and combining unit (114) for control thereof and beingarranged to provide the third signal strength representation signal (R₃)to a user presentation unit (120) for communication link check. 10.Portable communication device according to claim 9, wherein the portablecommunication device (102) is a cellular telephone.